Microsoft announced late Wednesday that it has sent four 64-bit versions of Windows into mass production. Windows XP Professional x64 as well as the server editions 2003 Standard x64, 2003 Enterprise x64 and 2003 Datacenter x64 are expected to be available in late April.
Better late than never - Microsoft finally has finished work on its first 64-bit client operating system. Windows XP Professional x64 was released together with three server Editions of the software to manufacturing. The development track of the client software is plastered with a series of delays, but Microsoft kept its most recent promise made at the Spring Intel Developer Forum to ship the software in the April timeframe.
Microsoft will officially announce the operating systems at WinHEC 2005, which is held from April 25 to 27 in Seattle. Commercial availability of the client and server packages is indicated as “late April”.
Source: Tom's Hardware